It has been known to impregnate foam pads with volatile agents for the purpose of slowly releasing these agents over a period of time. U.S. Pat. No. 4,339,550, for example, describes a foam product impregnated with volatile, active materials such as medicaments, perfumes, deodorants, germicides, pesticides, and disinfecting and sterilizing agents. The agents are incorporated into the cell structure of hydrophilic polyurethane foam during the foaming process. However, do to the volatility of these agents, techniques must be employed to prevent the agents from being rapidly released. These techniques include using an irreversible chemical reaction which causes the volatile material to become an intricate part of the foam structure; controlling the pore size of the polyurethane foam structure to permit only a portion of the volatile material to be released; and using a variety of controlled release ingredients that aid in producing in a sustained releases.
It is also known to incorporate nonvolatile agents into foam pads for the care and topical treatment of the skin. U.S. Pat. No. 5,762,946 describes a foam pad having a skin conditioning agent, in powder form, arranged at the center of a sheet of foam. The sheet is superimposed with another sheet such that the powdered product is incorporated between the two sheets. U.S. Pat. No. 5,762,946 also describes a foam pad in which the skin conditioning agents are incorporated into the foam pads after the foam has been produced by impregnating the polymerized foam products with a solution containing the skin conditioning agent and then dehydrating the foam product. However, adding the non-volatile agents into the post-polymerization foam structure permits the incorporation of the skin conditioning agents only into the open cell structure of the foam and prevents any substantial retention of the additive or long lasting release benefit.